Authorities have opened an internal investigation after video footage emerged showing South African police fatally shooting a robbery suspect while he was on the ground, wounded.

The CCTV footage, posted on the website of South Africa's Sunday Times newspaper, shows the suspect being shot at close range and also kicked as he lies on a sidewalk last month in Krugersdorp, west of Johannesburg.

The man, identified as Khulekani Mpanza, had allegedly earlier fired on police, according to South African media. In the video, Mpanza appears to drop a pistol as he falls to the ground after being shot the first time.

The African News Agency quoted police Lieutenant General Lesetja Mothiba as saying any police officers who acted unlawfully will be prosecuted.

South African police have been accused of brutality in the past. In 2013, a Mozambican taxi driver died after being dragged in the street from a police vehicle in an incident that was filmed while a crowd watched. Eight former police officers involved in the death were convicted of murder this year and await sentencing.

Police are under threat in a country with a high rate of violent crime, South Africa's police minister, Nkosinathi Nhleko, said September 10. He noted then that 60 police had been killed so far in 2015, 27 of them while on duty.